Can You Restain Concrete? (How-To)

I’m guessing you want to restain your concrete surface since you don’t like the existing stain anymore or maybe the old stain is starting to fade. Whatever the reason, can you restain the concrete?

You can restain already-stained concrete as long as the existing stain isn’t defective or filthy. If the old stain is filthy or the stain has been damaged by moisture, you’ll need to remove it before restaining.

Also, you’ll need to sand the existing stain with fine-grit concrete sandpaper to allow the new stain to stick to the concrete surface. You should know that stains usually appear lighter when used over already-stained concrete.

So why do stains appear lighter, is there a way to fix it, and can you stain over acid-stained concrete? The answer to these questions and more will be revealed in this post. So let’s dive in.

Can You Restain Colored Concrete?

Can You Restain Colored Concrete?

You can restain colored concrete but your best bet to achieve a good finish is to use an acid stain on the existing concrete. If you use a regular stain on the concrete, the stain will not penetrate in the least. This is because of the hard nature of the concrete.

Ordinarily, staining concrete is difficult because concrete is a very hard and strong surface. Now, when the concrete has an existing stain, it makes the concrete extra hard so the stain can’t soak in the concrete at all. This is why it’s better to restain colored concrete with an acid stain. Acid stains are designed to etch and soak into the concrete to reveal the best color so an existing stain will not be a problem for the acid stain.

You should know that if the colored concrete was sealed, you’ll need to remove the entire finish. In this case, you can’t restain the colored concrete since sealants make it impossible for the stain to have any adhesion to the concrete. So the sealant has to be removed to make the stain stick. You can remove the sealant by scraping, sanding, or stripping it off.

You can also restain colored concrete using a solid stain. Solid stains don’t need to penetrate as much into the concrete so the stain will stick fine. Also, solid stains have more pigments or color meaning that the stain is deep enough to cover the existing stain.

Can You Restain Concrete a Different Color?

Can You Restain Concrete a Different Color?

You can restain concrete a different color but it’s not advised to do so. If you restain concrete a different color, the color of the existing stain will clash with the color of the new stain.

The reason for this is that stains don’t penetrate concrete properly. Since the stain can’t penetrate the concrete deeply, the color of the stain will appear lighter or faded. If you use a different color of regular stain over already-stained concrete, the spot will appear unfinished because the regular stain will just not stick.

If you are to stain already-stained concrete, it’s better to use the same color. If you use the same color as the existing stain, the new stain coating will act as a touch-up. This will make the whole finish appear vibrant. This is better than applying an entirely different stain color.

However, if you want to use different colors of stain, there is a way to go about it. The hack is to apply concrete paste over the existing stain to seal the spot. Then apply a few coats of a different stain color over the concrete, preferably acid-stain.

Now, let’s check out how to restain concrete.

How To Restain Concrete?

Before we go on, here are a few tips you should remember in this task.

  • If the existing stain was sealed, you need to remove it from the concrete
  • Acid-stains work best on concrete
  • You should sand the existing stain to allow the new stain to stick better.
  • It’s better to remove damaged stains than staining over them
  • It’s better to use the same color as the existing stain.

To stain over already-stained concrete, you’ll need the following tools and supplies:

  • Concrete sandpaper
  • A gallon of acid stain for concrete
  • Paint thinner
  • A degreaser or concrete cleaner
  • Rags
  • A pair of gloves
  • A paintbrush or spray gun
  • An acrylic-based sealant

Here is a -step guide on how to stain over already-stained concrete:

1. Clean and Degrease The Concrete

Clean and Degrease The Concrete

The first step is to clean and remove grease and oils from the existing concrete stain. You can use rubbing alcohol, TSD, white spirits, methylated spirits, or concrete cleaner to remove grease from the concrete. You can also wash the concrete if it’s very filthy but be sure to leave it to dry for at least 3 days before staining.

2. Sand The Existing Stain On The Concrete

Sand The Existing Stain On The Concrete

This step is very important. The existing stain has to be properly sanded to allow the new stain to stick. You should sand the concrete stain with fine-grit concrete sandpaper.

This helps to remove bumps and improves adhesion for the new stain. If the existing stain has a sealant or top coat, here is where you need to remove the sealant. If you don’t, even the acid stain will not stick. To easily remove the sealant, pour some mineral spirits on it, leave it for ten minutes, and scrape off after with a paint scraper.

The next step is to remove the dust and mess that you created while sanding or removing the existing stain. You can do this with a rag.

3. Apply Acid Stain

Apply Acid Stain

You can apply the acid stain once the concrete is prepped, clean, and dry enough to accept the stain. You should test the acid stain on an area of the concrete to see how the stain goes on.

Some DIYers prefer wetting the concrete before applying the acid stain. It’s reported to help with adhesion so it’s a trick that you can try.

Ensure to allow each coat of the acid stain to penetrate and set in the concrete before recoat. Acid stains take between 5 and 48 hours to fully dry on concrete. On average, the acid stain will dry completely in 24 hours.

4. Seal The Stain (Optional)

Seal The Stain

You can choose to or not to seal the stain but sealing makes the stain last longer. Also, sealing the stain can make the light finish appear deeper depending on the type of sealant that you use.

If you apply was, the stain color will appear deeper. It’s generally advised to use an acrylic-based or water-based sealant over the acid stain to prevent a reaction with the chemicals and solvents in oil-based sealants.

Can You Stain Over Acid-Stained Concrete?

You shouldn’t stain over acid-stained concrete. If you do, there is a probability that the finish will not come out smooth. Also, the color of the stain will appear faded or untouched.

The reason for this is because of the way acid stains are set in concrete. When you apply acid stain over concrete, the stain will etch and eat into the concrete material. Then through a chemical reaction, the color sets inside the concrete.

The best way to stain over or change the color of acid-stained concrete is to apply a few coats of concrete paste over the existing acid stain. Then wait for the concrete paste to cure before restaining.

You can also try applying an acid stain of the same color as the existing acid stain. The new stain will look better if the colors are the same. You should only apply an acid stain or a water-based stain over an acid stain. Never apply oil-based stain or sealant over acid stain to prevent reactions.

How Long Does Stained Concrete Last?

Stained concrete generally doesn’t last more than 4 years on concrete. Concrete stains last between 18 months and 4 years on concrete. The reason for the short life span of concrete stains is that stains by design are generally not durable.

Unlike paints, stains are designed for beauty and not for protection. Stains will make the concrete look better but the finish can be quickly ruined by moisture, scratches, and dirt.

Also, concrete surfaces usually experience heavy usage, foot traffic, weight, and oils. Having a not-so-durable stain over a concrete surface that will experience heavy use will cause the stain to give way quickly and easily.

However, you can make the concrete stain last longer by sealing it. When you seal the stain, the sealant will dry to form a hard moisture resistant film that will help the concrete stain cope better with its harsh environment.

On average, sealed stains last at least 6 years on concrete. Stains sealed with 2-part epoxy can last over 8 years on concrete.

Final Words

Overall, you can restain concrete as long as you follow the tips above. Also, don’t use regular stains over already stained concrete as it won’t stick properly and if you want the stain to last longer, you should seal the stain.

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